Piston and ring construction



March 29, 1934. X $u 1,951,959

FIST-ON AND RING CONSTRUCTION Filed May 25, 1930 5 Sheets-Sheet l March 2@, 1934. A. M. ALEXANDRESCU 3 PISTON AND RING CONSTRUCTION Filed May 23, 1930 5 Sheets-Sheet 2 March 2% 11934. A. M. ALEXANDRESICU 1,951,959

PISTON AND RING CONSTRUCTION Filed May 23, 1930 5 Sheets-Sheet 3 March 20, 1934.

A. M. ALEXANDRES CU PISTON AND RING CONSTRUCTION Filed May 23, 1930 5 Sheets-Sheet 4 2%, fiiazammw mm W W GtforncgS.

A. M. ALEXANDRESCU PISTON AND RING CONSTRUCTION Filed May 23, 1930 5 Sheets-Sheet 5 March 20, 1934.

Patented use. as, rear.

STATES 8 (Claims.

The present invention relates to piston and ring construction and has for an object to provide an improved construction of piston and an improved construction and arrangement of rings for cooperating therewith for effectively sealing the piston when used in internal combustion engines to maintain proper combustion in the cylinders, and to prevent seepage of oil past the piston from the crank case.

Another object of the present invention is to provide an improved construction of piston for catching and distributing the lubricant between hind the rings and to the interior of the piston.

A further object of the invention is to providea cooperating construction of piston ring groove and combined ring structure, whereby the ring may automatically take up inaccuracies of width of groove occasioned in either manufacture or incident to wear, and which, cooperating with piston lubricating construction, will maintain the piston, after wear, tightly and from vibrating and knocking in the cylinder.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views.

Figure 1 is a fragmentary vertical section taken through an internal combustion engine showing a piston and ring constructed according to the present invention mounted therein, the dotted lines showing the lowermost position of the piston.

Figure 2 is a fragmentary section taken through the same axially at right angles on the line 2-2 of Figure 1.

Figure 3 is a fragmentary vertical section similar to Figure 1, but showing the piston in side elevation.

Figure 4 is a view similar to Figure 2, but showing the piston in side elevation.

Figure 5 is a reduced transverse section taken on the line 5-5 of Figure 3.

Figure 6 is a similar view, but taken on the line 6-6 of Figure 4.

Figure 7 is a fragmentary sectional view similar to Figure 4, but showing a modified construction of piston partly in section, and showing a force feed lubricating means therefor.

Figure 8 is a similar view, but taken axially at right angles on the line 8-8 of Figure '7.

Figure 9 is a transverse section taken through the modified form substantially on the line 9-9 of Figure 8.

Figure 10 is a like view taken on the line 10--10 of Figure '7.

Figure 11 is a fragmentary vertical section taken through a cylinder with a piston therein, partly in section, and showing another modification in the construction.

Figure 12 is a transverse section taken on the line 1212 through Figure 11,

Figure 13 is a longitudinal section taken through a locomotive cylinder and piston mounted therein, showing the mounting of the piston rings therein.

Figure 14 is a transverse section taken through the same substantially on the line 14-14 of Figure 13.

Figure 15 is a vertical fragmentary section taken through the cylinder of an internal combustion engine, showing partly in elevation and partly in section another modified form of the piston.

Figure 16 is a transverse section taken through the same substantially on the line 1616 of Figure 15.

Figure 17 is a like view, but taken on the line 1'7--17 of Figure 15.

Figure 18 is a fragmentary vertical section taken through a cylinder of an airplane motor, or compressor showing a further modification of piston, and means of forced lubrication therefor.

Figure 19 is a transverse section taken through the same on the line 1919 of Figure 18.

Figure 20 is a similar view taken on the line 20-20 of Figure 18.

Figure 21 is a fragmentary enlarged horizontal section taken from Figure 16, and showing the and lower edges thereof.

Figure 24 is a detail fragmentary sectional view of a portion of the piston, showing the ring groove therein, and illustrating diagrammatically the various angular positions of the opposite walls thereof. 4

Figure 25 is a plan view of the-ring spreader employed.

Figure 26 is a similar view of a slightly modifled form of the spreader.

Figure 2'7 is a fragmentary outer side elevation of a portion of the ring spreader shown in Figure 25.

Figure 28 is a transverse section through the same taken on the line 28-28 of Figure 25. Referring to the drawings, and first to Figure 1, 30 designates the cylinder of an internal combustion engine of any suitable type, which is provided with a head 31, suitably mounted thereon, and forming therewith a compression chamber 32. The cylinder 30 is provided at one side with a valve spring case 33, in which is disposed the springs 34 and tappets 35, the case 33 having a closure plate 36 sealed against its outer side for maintaining therein a bath of oil 37.

The side of the cylinder 30 is provided with an oil passage 38, which leads from the lower end portion of the valve spring case 33 for conducting oil from the oil bath to the interior of the cylinder, and against the piston located therein.

The improved piston disclosed in Figure 1 comprises a hollow cylindrical body part 39, having at its upper portion peripheral ring grooves 40, which are relatively wide and adapted to receive composite piston rings composed of spaced annular sections 41 urged apart by intermediate wedge sections 42. The opposite walls of each piston groove 40 flare outwardly, and the spaced sections 41 of the ring have their outer surfaces correspondingly bevelled or inclined to bear against the sides of the ring groove 40, and have their inner opposite faces bevelled or inclined to slidably receive thereagainst the opposite inclined faces of the wedge sections 42.

The piston 39 is provided at its interior with longitudinally extending webs or reinforcements 43, which taper downwardly toward the lower portion of the piston, and adjacent to the depending skirt 44. The piston 39 is provided immediately below the ring section thereof, with an inwardly and upwardly inclined oil collecting flange 45 of suitable depth, and disposed at a suitable angle for collecting oil, and deflecting the oil through one or more peripheral slots to the piston.

The oil grooves or passages, being located immediately' below the ring section, serve as vents for oil accumulating beneath the rings, so that .the oil may escape inwardly over the collecting flange 45. Thus the flange 45 and the slots 46 serve to relieve excess accumulation of oil, and also serve to supply oil when such is lacking.

The intermediate portion of the piston 39 is provided with a plurality of cross grooves 4'7, which are cut into the peripheral surface of the piston, and extend substantially spirally thereabout, and intersect one another at desired points, the free ends of the cross grooves 4'7 opening into the slots or passages 46, so as to receive oil accumulating therein, and spread the oil uniformly over the peripheral surface of the piston.

The intermediate portion of the piston carries the usual trunnions 48 in which are mounted bushings 49 for supporting the usual wrist pin 50. The piston is provided in opposite sides, in registry with the outer ends of the trunnions 46, with flat faces provided with vertical grooves 51, which open at their upper ends into the S Q S 46 to re:

ceive the oil therefrom, and which also 0 11 into the cross grooves 47 for insuring the rapi spread of the oil over the outer surface of the piston. The trunnions 48 are provided with oil passages 52 therein, which lead inwardly and downwardly from the point of mergence between the circumferential slots 46 and the vertical slots 51, as shown in Figure 2.

The piston is also provided at its outer wall with a longitudinally extending oil slot 53 which is spaced between the slots 51 and adapted to register at times with the oil passage 38, which leads from the oil bath in the valve spring case 33 for supplying a quantity of "oil to the groove 53 each time the piston moves inwardly toward the end of its stroke. at its lower end into an annular oil groove 54, which extends entirely around the piston, and which intersects the intermediate portion of the cross grooves 4'? for supplying a charge of oil to the upper and lower portions of said cross grooves 47. The lower portions of the grooves 47 extend through the skirt 44 of the piston and open through the lower edge thereof, the said edge of the skirt 44 being preferably turned inwardly as shown.

The webs or reinforcements 43, which are arranged longitudinally within the upper part of the piston 39, provide the sole connection between the parts of the piston 39, which are located above and below the circumferential passages or slots 46. In the modification shown in Figure 7, the wrist pin 55 opens directly into the end slots 51, and the cylinder 56 is provided opposite one of the grooves 51, when the piston is in its lowermost position with an oil supply conduit 57 adapted to deliver oil under pressure directly into the hollow wrist pin 55, and also into the oil groove 51. It is apparent that during .the movement of the piston past the oil conduit 57 that oil will be discharged into the slots 51 throughout thelength thereof, so that the oil under pressure will be properly distributed into the various grooves and passages of the exterior surface of the piston, as well as into the wrist pin 55. The wrist pin 55 is provided with the usual oil openings 58, which conduct the oil to the surface thereof.

The lower part of the piston is provided'with a plurality of longitudinally disposed expansion slots 59, which open through the outer peripheral surface of the piston, and which extend inwardly by virtue of interior U-shaped ribs 60, dividing the outer surface of the piston into a plurality of segments adapted for expansion and contraction toward and from one another.

Referring now to the construction shown in Figures 11 and 12, it will be noted that the piston is divided into three sections, an'upper ring section 61, an intermdiate piston section 62, and a lower skirt section 63, these parts being intercommunieating and held together by longitudinal .webs or ribs 64, which extend throughout substantially the entire length of the piston. It will be noted that the ring section 61 and the intermediate section 62 are slightly spaced apart, as before described, to provide the annular recesses or slots 46, and like circumferential slots or grooves 65 are provided between the intermediate section 62 and the lower skirt section 63. It will be noted that these slots 65 intersect the cross grooves 47, and that the lower slots 65 are provided at their lower edges with a collector flange or lip 66, similar to the lip or flange 45 heretofore described.

Referring now to Figures 13 and 14, 67 designates a cylinder of a steam engine or the like,

This oil groove 53 opens such as a locomotive, and has therein a piston 68 provided with relatively wide ring grooves 69, having spaced ring sections 70 and 71, the outer surfaces of which conform to the opposed walls of the ring groove, so as to seat fiat thereagainst to seal the ring in the groove. The inner edges of the ring sections 70 and 71 are inclined outwardly toward each other to receive therebetween an annular wedge section 72, normally urged by its inherent resiliency between the sections 70 and 71 to at all times maintain the same in spread and outwardly urged position. The wedge section 72 ofthe ring may be provided with oil or compression passages 73 leading through the section 72 to equalize pressure at the opposite faces thereof.

In Figures 15, 16 and 17, there is shown a construction which is preferable in use in large bore motors, although it may be used in small bore motors. The structure is adapted for use only with the splash system of lubrication. In this form, the upper part of the piston 74 is provided with the ring grooves 75 provided with composite piston rings therein, as above described, and which have wedge sections 76 with grooves or recesses 77 in the upper and lower faces thereof, leading from the outer to the inner sides of the wedge section 76 for equalizing pressure at its opposite sides and for admitting the passage of oil or compression behind the rings. The lower ring groove 75 is vented to the interior of the piston 74 by a plurality of openings 78, which lead through the inner wall of the piston, so that accumulation of oil and pressure behind the lower ring may be vented to the interior of the piston.

Immediately below the ring section of the piston 74 the latter is provided with an exterior annular oil groove '79, the lower wall of which is inclined outwardly and downwardly, and provided with a plurality of openings or perforations 80, which extend through the wall of the piston and relieve pressure and oil accumulation in the groove-79 to the interior of the piston.

The lower portion of the piston 74 is provided with a second annular oil groove 81, the lower wall of which forms substantially a continuation of an upwardly and inwardly directed oil catching flange 82, which extends inwardly beyond the inner wall of the piston and provides a pocket at the upper side of the flange 82 for entrapping a quantity of the oil splashed up into the piston. The upper wall of the groove 81 is provided with a desired number of oil passages 83, which open into the bottom of said pocket, so that the oil entrapped above the flange 82 may flow down into the groove 81, encircle the piston, and flow upwardly and downwardly through the cross grooves 47.

If desired, ring spreaders may be employed, such as shown in Figures 15 and 16, and which are disclosed as being disposed behind the two lower piston rings. These Spreaders may be constructed as shown in Figures 25, 27 and 28. The spreader comprises an annular split band 84 of resilient material with an inherent tendency to spread, and which is relatively narrow and adapted to seat behind the wedge section 76 of the ring.

At spaced intervals throughout the length of the band 84 are secured thereto by welding, riveting or other suitable means, a plurality of spring tongues 85, the same extending from the outer side of the band 84, and having transverse-- ly enlarged heel portions 86 of greater width than the band 84, and adapted to bear against the lower and upper walls of the ring groove 75 to maintain the spreader against vertical shifting in the piston is in 'its lowermost position.

the ring groove, and in correct alignment with the wedge section 76 of the ring.

These enlarged heel portions 86 also serve the purpose of providing amplev clearance beneath the lower edge of the band 84 for free passage of compression and oil from behind the ring through the openings 78 in the wall of the piston 74.

Figure 26 shows a slight modification in the construction of the spreader having the band 84, which carries a plurality of spring tongues 87, which extend on the band in a direction opposite to the direction in which the spring tongues 85 extend upon the band 84. Otherwise the construction is similar to the showing in Figure 25. Referring now to'Figures l8, l9, and 20, there is shown a cylinder 88 adapted for use particularly in airplane motors, compressors for very high compression, and the like, and which is provided with a piston 89. The piston 891s provided with the ring grooves 75 with the rings as hereinbefore described, and each comprise the spaced sections 41 and the expanding sections 76, with the walls of the ring grooves substantially in parallel relation, and the-piston 89 is also provided near its top with a. relatively small ring groove 90 of usual dimensions, and construction, which is fitted with the usual type of ring 91. This particular construction is resorted to for insuring a more easy operation of the rings when subjected to relatively high temperatures. The lower ring groove 75 is vented to the interior of the piston 89by the openings 78 hereinbefore described, and the pistonis also provided with the annular groove 79 having the openings through its lower wall, which vent the groove 79 to the interior of the piston 89.

The section of the piston 89 below the groove 79 is provided with the exterior cross grooves 47, which are intersected by the trunnions 92 for the wrist pin 93. The flat outer ends of the trunnions 92 provide spaces 94 for oil, which open into the adjacent ends of the cross'grooves 47 to insure proper distribution of the oil in all directions above, below, and around the exterior of the piston in opposite directions, as well as to the interior of the wrist pin 93.

For supplying oil to these parts of the piston,

the latter is provided with an exterior circumferential oil groove 95, which extends entirely around the piston, and intersects the oil space 94. At one side, the oil groove 95 opens into a vertically disposed slot 96 formed in the outer surface of the lower part of the piston 89, and

which is adapted to register with an oil feeding conduit 97 for supplying oil under pressure, the groove 96 registering with the conduit 97 when groove 96 is closed at its opposite ends, and not only opens into the annular groove 95, but also into the adjacent portions of the cross grooves 47. This insures a quick and even distribution of the oil under pressure, which is delivered through the pressure conduit 97.

Referring now to the diagrammatic illustration shown in Figure 24, the body 98 of the piston is provided with a. ring groove 99, which is substantially three times the width of the groove at present constructed in pistons, and which is shown to advantage in Figure 22. The opposed walls of the groove 99 are disposed substantially in parallel relation, as indicated by the lines 100, when the piston 98 is to be subjected to-relatively high temperatures, such as in airplane motors, compressors of high compression type, and the like, and where the ring groove 99 is located near This the upper part of the piston 98, as shown in Figure 22, and where the rings are subjected to intense heat. The reason for this construction is that the substantially parallel walls 100 offer but little resistance to the contraction of the rings when they are forced back into the groove 99 by expansion, and it is necessary in this type of engine and with grooves in the upper part of the piston, to offer as little resistance as possible to this contraction.

As shown by the lines 101, the side walls of the groove 99 may be diverged slightly where temperatures are not quite so high, and where the ring grooves 99 are spaced downwardly from the upper end of the piston, and toward the source of lubrication.

The lines 102 indicate a further divergence in the side walls of the groove 99, and this indicates the use of this type of groove for lower temperatures, or at points nearer the point of distribution of the lubricant.

In a like manner, the lines 103 indicate a further divergence in the side walls of thering grooves 99, showing that the divergence is proportionate to the temperature and to the location of the ring groovewith respect to the source of lubrication.

As shown in Figure 22, the straight wall groove 99 is near the upper end of the piston, and by use of the wedge section v'76, the spaced sections 41 are held outwardly against the opposite sides of the groove, and are also maintained in an outwardly expanded position. The parallel walls 100 of the groove and the outer parallel walls of the sections 41 offer but slight resistance to the compression of the ring as a unit without V disturbing the spread relation of the sections 41.

Of course, the wedge section I6 may be given any desired taper corresponding to the'inclined walls indicated in Figure 24. The innermost ring groove '75 is preferably provided with the outwardly flaring walls, as shown in Figure 22, so that the ring will bear with, greater pressure and resistance against the side wall of the cylinder 30, and any seepage of the gases ofcombustion, or of the lubricant past the sections 41 is .vented through the wedge section 76, into the groove 75, and through the-openings '78 to the interior of the piston 98.

Of course, any desired arrangement of the ring grooves may be used, and the ring groove '75 may he graduated as to the flaring of its walls.

It will be obvious that many changes in the construction, combination and arrangement of parts could be made, which could be used without departing from the spirit of my invention, and I do not mean to limit the invention to such details, except as particularly pointed out in the claims.

Having thus described my invention, what I claim and desired to secure by Letters Patent of the United States is:--

1.. In an internal combustion engine, comprising a piston having an upper ring section and a lower section connected thereto by internal ribs and providing an annular slot between the sections, the lower section having an inwardly and upwardly extending flange adapted to catch oil splashed up into the piston for passage outwardly through said slot, said piston also having below the annular slot and in its peripheral surface a plurality of grooves communicating with said slot for the reception of lubricant therefrom.

2. In an internal combustion engine, a piston having an upper ring section, and a spaced lower section connected thereto by internal ribs and providing an annular groove between the sections for free passage of lubricant into and out of the piston, said lower section having an annular oil groove spaced below said first groove, and provided at one side with a vertically disposed receiving groove communicating with the second oil groove, and adapted to receive oil from a source of supply for distribution to the second oil groove, said piston also having in its outer surface and in its lower section a plurality of cross grooves intersecting and communicating with both of said grooves and said annular slot.

3. In an internal combustion engine, a piston having an upper ring section and a lower lubricating section connected thereto by ribs and with an annular slot between the sections, said lubricating section having peripheral cross grooves therein opening at their upper ends into said slot, said lubricant section also having an annular oil groove intermediate its ends, and intersecting the cross grooves, and further provided with a supply groove in one side intersecting the cross grooves, and said annular oil groove.

4. In an internal combustion engine, a piston having an upper ring section and a lower lubricating section, with the sections connected by integral internal ribs and providing an annular slot between the sections, said lower section having wrist pin trunnions with fiat outer ends opening into said slot, said lower section also having an annular oil groove opening into said trunnions at the bottoms of the flat ends thereof, and provided with intermediate grooves opening into said slot and annular groove, and through the lower end of the lower section.

5. A piston comprising an upper ring section provided with a series of ring grooves therein and with openings leading through the wall of a lower ring groove to the interior of the piston, said piston having an annular groove at the bottom of said ring section, and provided with openings leading from said groove to the interior of the piston, said piston also having a second annular groove spaced below said first groove and with openings through the upper wall of said second groove leading to the interior of the piston, and provided in line with the bottom of said second groove and the opening leading therefrom with an upwardly and inwardly inclined oil entrapping flange for catching and directing oil through the openings into said second groove.

6. A piston comprising a ring section, a lower section beneath the ring section, an annular oil groove at the inner end of the ring section having a lower inclined wall with openings therethrough leading to the interior of the piston, said lower section having an intermediate annular oil groove spaced below said first groove and provided with a longitudinal oil receiving groove in its side. opening into said second annular groove adapted to receive lubricant under pressure for supplying lubricant to said second annular groove, said lower section of the piston also having exterior intermediate grooves intersecting both of said oil' grooves for distributing oil under pressure entirely about and throughout the length of said lower-section.

7. A piston for an internal combustion engine.

comprising a body portion having upper and 1 rar- * memes 8. A piston including a, skirt having in its outer surface a substantially circumferentielly continuous, sinuous oil groove including portions diagonally-leterelly inclined and terminal portions extending beyondadjacent intersecting groove portions. 

